Design of a computationally efficient observer-based distributed fault detection and isolation scheme in second-order networked control systems.

This paper presents a novel directional observer-based fault detection and isolation scheme for second-order networked control systems (NCS). The directional unknown input observer (UIO) tool is exploited to study the problem of distributed fault detection and isolation (FDI). Two design schemes with global and partial/local network models are proposed to solve the distributed FDI problem. Thresholds are computed for the application of the proposed schemes in a noisy environment. In addition, the salient features of the proposed schemes are that both fault detection and fault isolation are achieved in a single step using a single observer. The schemes are applied to power system models to validate their results. A detailed comparison with existing FDI schemes is also provided, which clearly shows the effectiveness of the proposed scheme in terms of computational requirements.

Distributed fault detection and isolation in second order networked systems in a cyber-physical environment.

Modern industrial processes and cyber-physical systems (CPS) are prone to anomalies both due to cyber and physical perturbations. Cyber disturbances or attacks being more hazardous may give birth to a series of multiple coordinated faults. In order to detect and isolate such faults, this paper proposes a novel distributed fault detection and isolation scheme for second-order networked systems. The system is assumed to be working in a cyber-physical environment where it is likely to face multiple simultaneous faults. Each node has access to measurements of states of its neighboring nodes. A distributed fault detection and isolation filter (DFDIF) is designed such that fault detection and fault isolation can be obtained in a single step. Using the proposed filter, each node can detect and isolate multiple simultaneous faults in its neighboring nodes. The detection and isolation of faults with a single filter at each node reduces the overall computational burden of distributed fault detection and isolation (DFDI) scheme. The proposed framework is tested for power network and robotic formations. Finally, a comparison with existing techniques is provided to prove the effectiveness of the proposed method.